gistfile1.txt

undefine@uml:~$ echo |openssl s_client -connect letsencrypt.org:443 -showcerts >x.pem
depth=2 C = US, O = Internet Security Research Group, CN = ISRG Root X1
verify return:1
depth=1 C = US, O = Let's Encrypt, CN = R3
verify return:1
depth=0 CN = lencr.org
verify return:1
DONE
undefine@uml:~$ openssl verify -CAfile x.pem x.pem 
C = US, O = Internet Security Research Group, CN = ISRG Root X1
error 2 at 2 depth lookup: unable to get issuer certificate
error x.pem: verification failed
undefine@uml:~$ grep DST /etc/ca-certificates.conf
!mozilla/DST_ACES_CA_X6.crt
!mozilla/DST_Root_CA_X3.crt
undefine@uml:~$ sudo vim /etc/ca-certificates.conf
undefine@uml:~$ grep X3 /etc/ca-certificates.conf
undefine@uml:~$ sudo update-ca-certificates --fresh
Clearing symlinks in /etc/ssl/certs...
done.
Updating certificates in /etc/ssl/certs...
rehash: warning: skipping duplicate certificate in UbuntuOne-Go_Daddy_Class_2_CA.pem
128 added, 0 removed; done.
Running hooks in /etc/ca-certificates/update.d...

Replacing debian:Actalis_Authentication_Root_CA.pem
Replacing debian:AffirmTrust_Commercial.pem
Replacing debian:AffirmTrust_Networking.pem
Replacing debian:AffirmTrust_Premium.pem
Replacing debian:AffirmTrust_Premium_ECC.pem
Replacing debian:Autoridad_de_Certificacion_Firmaprofesional_CIF_A62634068.pem
Replacing debian:Baltimore_CyberTrust_Root.pem
Replacing debian:Buypass_Class_2_Root_CA.pem
Replacing debian:Buypass_Class_3_Root_CA.pem
Replacing debian:CA_Disig_Root_R2.pem
Replacing debian:Certigna.pem
Replacing debian:certSIGN_ROOT_CA.pem
Replacing debian:Certum_Trusted_Network_CA.pem
Replacing debian:Chambers_of_Commerce_Root_-_2008.pem
Replacing debian:Comodo_AAA_Services_root.pem
Replacing debian:COMODO_Certification_Authority.pem
Replacing debian:COMODO_ECC_Certification_Authority.pem
Replacing debian:Cybertrust_Global_Root.pem
Replacing debian:DigiCert_Assured_ID_Root_CA.pem
Replacing debian:DigiCert_Global_Root_CA.pem
Replacing debian:DigiCert_High_Assurance_EV_Root_CA.pem
Replacing debian:D-TRUST_Root_Class_3_CA_2_2009.pem
Replacing debian:D-TRUST_Root_Class_3_CA_2_EV_2009.pem
Replacing debian:EC-ACC.pem
Replacing debian:Entrust.net_Premium_2048_Secure_Server_CA.pem
Replacing debian:Entrust_Root_Certification_Authority.pem
Replacing debian:ePKI_Root_Certification_Authority.pem
Replacing debian:GeoTrust_Primary_Certification_Authority_-_G2.pem
Replacing debian:Global_Chambersign_Root_-_2008.pem
Replacing debian:GlobalSign_Root_CA.pem
Replacing debian:GlobalSign_Root_CA_-_R2.pem
Replacing debian:GlobalSign_Root_CA_-_R3.pem
Replacing debian:Go_Daddy_Class_2_CA.pem
Replacing debian:Go_Daddy_Root_Certificate_Authority_-_G2.pem
Replacing debian:Hellenic_Academic_and_Research_Institutions_RootCA_2011.pem
Replacing debian:Hongkong_Post_Root_CA_1.pem
Replacing debian:Izenpe.com.pem
Replacing debian:Microsec_e-Szigno_Root_CA_2009.pem
Replacing debian:NetLock_Arany_=Class_Gold=_Főtanúsítvány.pem
Replacing debian:Network_Solutions_Certificate_Authority.pem
Replacing debian:QuoVadis_Root_CA_2.pem
Replacing debian:QuoVadis_Root_CA_3.pem
Replacing debian:QuoVadis_Root_CA.pem
Replacing debian:Secure_Global_CA.pem
Replacing debian:SecureSign_RootCA11.pem
Replacing debian:SecureTrust_CA.pem
Replacing debian:Security_Communication_RootCA2.pem
Replacing debian:Security_Communication_Root_CA.pem
Replacing debian:Sonera_Class_2_Root_CA.pem
Replacing debian:Starfield_Class_2_CA.pem
Replacing debian:Starfield_Root_Certificate_Authority_-_G2.pem
Replacing debian:Starfield_Services_Root_Certificate_Authority_-_G2.pem
Replacing debian:SwissSign_Gold_CA_-_G2.pem
Replacing debian:SwissSign_Silver_CA_-_G2.pem
Replacing debian:Trustis_FPS_Root_CA.pem
Replacing debian:T-TeleSec_GlobalRoot_Class_3.pem
Replacing debian:TWCA_Root_Certification_Authority.pem
Replacing debian:VeriSign_Universal_Root_Certification_Authority.pem
Replacing debian:XRamp_Global_CA_Root.pem
Replacing debian:ACCVRAIZ1.pem
Replacing debian:Atos_TrustedRoot_2011.pem
Replacing debian:DigiCert_Assured_ID_Root_G2.pem
Replacing debian:DigiCert_Assured_ID_Root_G3.pem
Replacing debian:DigiCert_Global_Root_G2.pem
Replacing debian:DigiCert_Global_Root_G3.pem
Replacing debian:DigiCert_Trusted_Root_G4.pem
Replacing debian:E-Tugra_Certification_Authority.pem
Replacing debian:QuoVadis_Root_CA_1_G3.pem
Replacing debian:QuoVadis_Root_CA_2_G3.pem
Replacing debian:QuoVadis_Root_CA_3_G3.pem
Replacing debian:TeliaSonera_Root_CA_v1.pem
Replacing debian:T-TeleSec_GlobalRoot_Class_2.pem
Replacing debian:TWCA_Global_Root_CA.pem
Replacing debian:CFCA_EV_ROOT.pem
Replacing debian:COMODO_RSA_Certification_Authority.pem
Replacing debian:Entrust_Root_Certification_Authority_-_EC1.pem
Replacing debian:Entrust_Root_Certification_Authority_-_G2.pem
Replacing debian:GlobalSign_ECC_Root_CA_-_R4.pem
Replacing debian:GlobalSign_ECC_Root_CA_-_R5.pem
Replacing debian:IdenTrust_Commercial_Root_CA_1.pem
Replacing debian:IdenTrust_Public_Sector_Root_CA_1.pem
Replacing debian:OISTE_WISeKey_Global_Root_GB_CA.pem
Replacing debian:Staat_der_Nederlanden_EV_Root_CA.pem
Replacing debian:Staat_der_Nederlanden_Root_CA_-_G3.pem
Replacing debian:USERTrust_ECC_Certification_Authority.pem
Replacing debian:USERTrust_RSA_Certification_Authority.pem
Replacing debian:AC_RAIZ_FNMT-RCM.pem
Replacing debian:Amazon_Root_CA_1.pem
Replacing debian:Amazon_Root_CA_2.pem
Replacing debian:Amazon_Root_CA_3.pem
Replacing debian:Amazon_Root_CA_4.pem
Replacing debian:Certum_Trusted_Network_CA_2.pem
Replacing debian:Hellenic_Academic_and_Research_Institutions_ECC_RootCA_2015.pem
Replacing debian:Hellenic_Academic_and_Research_Institutions_RootCA_2015.pem
Replacing debian:ISRG_Root_X1.pem
Replacing debian:SZAFIR_ROOT_CA2.pem
Replacing debian:TUBITAK_Kamu_SM_SSL_Kok_Sertifikasi_-_Surum_1.pem
Replacing debian:GDCA_TrustAUTH_R5_ROOT.pem
Replacing debian:GlobalSign_Root_CA_-_R6.pem
Replacing debian:OISTE_WISeKey_Global_Root_GC_CA.pem
Replacing debian:SSL.com_EV_Root_Certification_Authority_ECC.pem
Replacing debian:SSL.com_EV_Root_Certification_Authority_RSA_R2.pem
Replacing debian:SSL.com_Root_Certification_Authority_ECC.pem
Replacing debian:SSL.com_Root_Certification_Authority_RSA.pem
Replacing debian:TrustCor_ECA-1.pem
Replacing debian:TrustCor_RootCert_CA-1.pem
Replacing debian:TrustCor_RootCert_CA-2.pem
Adding debian:Certigna_Root_CA.pem
Adding debian:certSIGN_Root_CA_G2.pem
Adding debian:emSign_ECC_Root_CA_-_C3.pem
Adding debian:emSign_ECC_Root_CA_-_G3.pem
Adding debian:emSign_Root_CA_-_C1.pem
Adding debian:emSign_Root_CA_-_G1.pem
Adding debian:Entrust_Root_Certification_Authority_-_G4.pem
Adding debian:e-Szigno_Root_CA_2017.pem
Adding debian:GTS_Root_R1.pem
Adding debian:GTS_Root_R2.pem
Adding debian:GTS_Root_R3.pem
Adding debian:GTS_Root_R4.pem
Adding debian:Hongkong_Post_Root_CA_3.pem
Adding debian:Microsoft_ECC_Root_Certificate_Authority_2017.pem
Adding debian:Microsoft_RSA_Root_Certificate_Authority_2017.pem
Adding debian:Trustwave_Global_Certification_Authority.pem
Adding debian:Trustwave_Global_ECC_P256_Certification_Authority.pem
Adding debian:Trustwave_Global_ECC_P384_Certification_Authority.pem
Adding debian:UCA_Extended_Validation_Root.pem
Adding debian:UCA_Global_G2_Root.pem
Adding debian:NAVER_Global_Root_Certification_Authority.pem
done.
Updating Mono key store
Linux Cert Store Sync - version 4.6.2.0
Synchronize local certs with certs from local Linux trust store.
Copyright 2002, 2003 Motus Technologies. Copyright 2004-2008 Novell. BSD licensed.

I already trust 130, your new list has 128
Import process completed.
Done
done.
undefine@uml:~$ openssl verify -CAfile x.pem x.pem 
C = US, O = Internet Security Research Group, CN = ISRG Root X1
error 2 at 2 depth lookup: unable to get issuer certificate
error x.pem: verification failed
undefine@uml:~$ vim x.pem  # usunięcie ostatniego certyfikatu podpisanego przez DST)
undefine@uml:~$ openssl verify -CAfile x.pem x.pem 
x.pem: OK